Reciprocating refrigerant compressors, designed exclusively for refrigerant vapor duty, are over stressed during liquid slugging conditions where liquid refrigerant and/or oil are present in the piston cylinder. When handling large volumes of liquid refrigerant and/or oil, cylinder pressures can approach and exceed 3000 psi rather than 400 psi as would be the case for R-22 in normal operation where no liquid is present. This high pressure is due to the overall restriction of valve ports, lines etc. as well as the head and the fact that the discharge valves are cycling at, for example, 3450 cycles per second and cannot handle the greater mass of material that is present during liquid slugging without greatly increasing the chance of damaging the suction valves. To withstand pressures this high would require strengthening of several components and there could be a reduction in long term reliability. The resultant unit would also be more massive and expensive to manufacture. Also, the relatively fragile suction valves are subject to permanent deformation at these elevated pressures.